Automatic type-writer-ribbon-reversing mechanism.



T. E; BUSCHMANN. AUTOMATIC TYPE WRITER RIBBON RBVERSING MEGHANISM. APPLICATION FILED FEB. 21, 1910.

w l rn/Ess E5 '1HE NoRRls PETERS co., wAsHlIyzrroN, D. c.

UNiTn s'rnrns narnia nro.

THEODOR EUGEN BUSCHMANN, OF CHEMNITZ, GERMANY, ASSIGNOR T0 THE FIRM OF WANDERER WERKE VORM. WINKLHOFER @c JAENICKE A. G., 0F SCI-IONAU, NEAR CHEMNITZ, GERMANY.

AUTOMATIC TYPE-WRITER-RIBBON-REVERSING MECHANISM.

Specification of Letters Patent.

Patented N ov. 29, 1910.

Application led February 21, 1910. Serial No. 545,151.

To all whom t 'may concern:

Be it known that I, THnoDoR EUGEN BUSGHMANN, engineer, subject of the Emperor of Germany, residing at Chemnitz, Neefestrasse 51, Saxony, Germany, have invented new and useful Improvements in Automatic Type Wvriter Ribbon Reversing lt/Iechanism, of which the following is a specification.

This invent-ion relates to mechanism for automatically reversing the longitudinal direction of the ink ribbon feed in typewriting machines, wherein a lever, hereinafter referred to as the feeler, is brought to bear on the periphery of one of the spools for the ribbon and effects a longitudinal movement of the spool driving shaft, and the release of the other spool of ribbon, the

larrangement being such that a. pawl elastically connected with the feeler comes into engagement with the threads of a worm mounted on the spool driving shaft, without altering there-by the tension of the ribbon, such engagement occurring when the ribbon is nearly all drawn olf. The elastic connection between the feeler and the pawl is so adapted that the pawl, once it is inserted in the threads of the worm, cannot be pulled out again by the reciprocating motion of the feeler caused by the occurrence of kinks or folds in the ribbon or by loosely wound places in the spool. The strengthened end of the ribbon is intended to effect the rapid disengagement of the pawl.

The object of the present invention is a special form of construction of the above described mechanism.

An essential characteristic of the invention to be now described consists in only those swinging movements of the feeler directed to the center of the spool being imparted to the pawl, the latter being usually freely movable so that the feeler only needs to give a single, very exact-ly adjustable short shock, in order to allow the outermost point of the pawl tobe engaged by one of the threads on the worm, and thus cause the pawl to completely engage the worm, until it strikes against a rigid attachment, when the reversal of the ribbon will take place in the well-known manner. The result of such an arrangement is that the ribbon is completely used for the whole of its length since the ribbon is only moved forward approxi- I mately 1 cm. between the moment of the shock and the complete reversal of the direction of motion of the ribbon.

A further characteristic of the present invention is the positive connection of the two pawls, since they are prevented thereby from engaging at the same time in the corresponding worms; whenboth ribbon spools are removed, the two pawls are always automatically disengaged from the worms.

Reference will now be made to the accompanying drawing, wherein mechanism according to the present invention is illustrated by way of example.

In said drawing F igure l is a front elevation of the whole mechanism; Fig. 2 is a plan view of same, one ribbon spool and the feelers being shown in thin lines, so as to show the parts lying underneath as plainly as possible.; Figs. 3 and 4 are plan views and illustrate two different positions of the mechanism for the left-hand spool gear, and Fig. 5 is a section on the line A-B of Fig. 3 viewed in the direction of the arrow.

Although not forming part of my present invention, but in order that the invention may be more readily understood I will first describe the device for insuring that the bevel wheels are normally in mesh. At the right-hand spool gear, there is pivotally mounted on a bolt 13, placed in the machine frame, a two-armed lever 12, the lower arm of which is fork-shaped at the end and engages in a circular groove in the spool driving shaft 1, while the upper arm of the lever is wedge-shaped, is situated beneath a roller 14 and has either its surface 15 or 1G in contact with the roller, the latter being carried on the free end of a leaf spring 17. The method of working is as already known.

According to my invention each ribbon spool driving gear is constructed as will now be explained in the following description for the left-hand spool 8 only. On the spool driving shaft 1 are rigidly fixed the already known bevel wheel 2 and the worm 27 which in this case are, however, formed of one piece so as to simplify the manufacture, the assembling and the adjusting of the mechanism. The bevel wheel 2 is not in mesh with the bevel wheel t on the spool shaft 6, because the ribbon 29 is still being unwound from the spool 8 belonging to the left-hand gear. Near to the side of, but behind, the worm 27 is mounted to rock in the horizontal plane around a bolt 34 the small pawl Q3 arranged in a slot in an arm 34 which is rigidly connected to the machine trame. At the other side of the bolt 34 there is a stop lever extension 33 formed in one piece with the pawl 23. To this lever there is suspended and rigidly connected by means of a small bolt 35 (Figs. 2-5 a curved angular lever, 35, 3T, 38, 39, 40, in such a manner that this latter lever can also be rotated around a downward extension of the bolt 34 (Fig. 5).

The upper end of the well-known :teeler shaft 2O is provided with the feeler 21, while from the lower end projects a lever 4l which is provided with a rigid projecting pin 42 extending into the yspace bounded by the curved angular lever 36, 37, 38, 39, and thereby imparts to the pawl 33, 23, by means ot the arms 38 and 39 of the curved angular lever, all the movements of the feeler 2l directed toward the center of the spool. The lever 4l is extended past the shaft 2O and formed into a hand grip or lever 43, which enables the feeler 2l to be lifted as desired trom the ribbon spool when it is desired to remove the spool trom the spool shaft G, this teeler being improved by the addition of a pressing roller 44 (Fig. l). Also in this movement et the feeler shaft Q0 the curved angular lever bv means of its arms 3G, 37, forms a limit of the path for the projecting pin 4Q, so as to prevent the extended or stretched band from being damaged through the feeler 21 oscillating too far. The force required tor pressing the Jeeler 2l against the periphery of the ribbon spool is provided in the well-known manner by a coil spring 2G, which also imparts to the shaft 2O a rotational movement in the corresponding direction.

rl`he right-hand gear for the ribbon spool 9 is arranged in exactly the same manner as described above for the left-hand gear; the pawls Q", 24 of both sides are, however, no longer only dependent on the eelers belonging thereto, but are also pivotally and positively coupled together by means of a connectiug rod 45. This rod extends between the two eye piece attachments 40 and 40 provided in the two curved angular levers, and is pivotally connected at both ends, while small coil springs 47 are provided between the heads of the bolts 46 and the ends of the rod; these small springs are for the purpose ot producing a pressure on the friction surface between the curved angular levers and the rod 45, this pressure completely preventing any accidental motion of the pawls Q3. Q4 which are otherwise perfectly free. The length ot the rod 45 is so calculated that when both ribbon spools 8 and 9 are removed from the spool shafts 6 and 7 and both eelers Q71 and 22 are in their between the curved angular lever arms 3S f' and 3f), both pawls 23 and 24 being then out of gear with their corresponding worms 27 and 2S. This latter condition would also occur when both feelers are lifted from the spools S and 9 by means of the hand grip I or lever 43, but then the projecting pins 4'2 lie againstthe angles formed by the lever arms 36 and 37.

The operation of the above described improved meehanism is as followr :HAC- cording to Figs. l and 2, the ribbon Q9 is completely wound etil the spool S on to the spool 9. Consequently the 'teeler 2l' has approached the axis ot' rotation ot the spool 8 and the projecting pin 42 olf the lever 4l. has rotated the curved angular' lever 3G, 37, 33, 39, 40, together with the pawl 23, rigidly connected thereto, to the lett away from the center position such a distance that the point of the pawl 23 has just come into gear with a thread of the worm 27. Consequently immediately the shaft l rotates farther, the teeler having no influence now any more, the thread ot the worm will grasp the point otl the pawl and quickly turn the easily rotatable pawl completelv into the thread groove ol the worm, until, as shown in Fig. 3, the projecting lever arm 33 is stopped by the arm 34 of the trame of the machine. From this moment onward the longitudinal motion oi the shaft l begins, this being caused by the worm rotating backward `against the now rigid pawl 23, whereby the wedge-shaped point ot the safety lever 12 arranged at the right-hand gear lifts the spring pressed roller 14 a little. As soon as the lever l2 has exceeded its middle position only by a little, the roller 14 snaps down again into the other wedge surface l5 and in this manner automatically completes the longitudinal motion of the shaft l. Fig. 4 illustrates this position; it also shows, at the same time, that the shaft l is only pushed a little past the middle position by means of the worm 27, so that when the longitudinal motion has been completed the pawl 23 is again just outside the reach of the worm, and consequently when the pawl oscillates back the point ot the pawl will not touch the right-hand thread of the worm.

It will be seen from the illustration of the mechanism that the new device Oilers no chance oit the longitudinal motion of the ribbon being accidentally reversed in anA impracticable manner. No matter how badly the ribbon is wound on the spool, the tightest wound place ot the spool will always determine the correct moment for reversing the motion, since the shock eti'ect- :LOL

ed by the feeler, even when the shock acts only for a moment, is still permanent for the pawl and will insure the reversing motion taking place. That is to say, the ribbon can be allowed to unwind until the core of the spool is exposed, the piece of the ribbon remaining on the core still being long enough for the reversing motion.

I claim l. In mechanism for reversing the longitudinal direction of motion of the ink ribbon in typewriters, the combination with a frame, two spool shafts mounted therein each having a gear wheel, and carrying a spool, a ribbon on the spools, .two springcontrolled feeler shafts each having a feeler adapted to coact with one of the spools, and driving means attached to each feeler shaft, of a revoluble and axially-movable shaft having two worms and two gear wheels adapted to mesh alternately with the former gear wheels, two pawls each adapted to engage with a worm, means positively connecting said pawls, and means connected with cach pawl and adapted to be actuated by said driving means for alternately bringing each pawl into engagement with one of the worms.

Q. In mechanism for reversing the longitudinal direction of motion of the ink ribbon in typewriters, the combination with a frame,` two spool shafts mounted therein each having a gear wheel, and carrying a spool, a ribbon on t-he spools, two springcontrolled feeler shafts each having a feeler adapted to coact with one of the spools, and driving means attached to each feeler shaft, of a revoluble and axially-movable shaft having two worms and two gear wheels adapted to mesh alternately with the former gear wheels, two pawls each adapted to engage with a worm, a rod positively connecting said pawls, and an angle lever connected with each pawl and adapted to be actuated by said driving means for alternately bringing each pawl into engagement with one of the worms.

3. In mechanism for reversing thelongitudinal direction of motion of the ink ribbon in typewriters, the combination, with a frame, and a revoluble and axially-movable shaft having two worms mounted therein, of two pawls adapted to engage alternately in said worms, each pawl having an arm for limiting the motion thereof in one direction by abutting against the frame, a rod pivotally connecting said pawls, and means for driving said pawls.

4. In mechanism for reversing the longitudinal direction of motion of the ink ribbon in typewriters, the combination, with a frame, and a revoluble and axially-movable shaft having two worms mounted therein, of two pawls adapted to engage alternately in said worms, each pawl havingan arm for limiting the motion thereof in one direction by abutting against the frame, a curved angle lever secured to each pawl, a rod positively connecting the angle levers, and means for driving the angle levers, the motion of the angle levers being limited in both directions by the frame, substantially as shown.

5. In mechanism for reversing the longitudinal direction of motion of the ink ribbon in typewriters, the combination, with a. rod (l5), of an angle lever (36, 37, 38, 39) carrying a bolt (i6) passing through said rod, a spring (e7) around said bolt pressing said rod on said lever, and a pawl (23, 33) secured on said lever, substantially as shown and for the purpose specified.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

l/Vitnesses FRITZ GRUNERT,

M. F. BENNDORF. 

